Pneumothorax (pneumothorax) is a condition in which gas enters the pleural cavity and causes a pneumatosis, called a pneumothorax. There are usually three major categories: spontaneous pneumothorax, traumatic pneumothorax and artificial pneumothorax. Spontaneous pneumothorax is caused by the rupture of lung tissue and dirty pleura due to lung disease, or by the rupture of tiny vesicles and pulmonary blisters near the lung surface, and the air in the lungs and bronchi enters the pleural cavity.
Disease classification
Spontaneous pneumothorax can be classified into primary spontaneous pneumothorax (PSP) and secondary pneumothorax (SSP) according to the presence or absence of combined lung diseases before the occurrence of pneumothorax. Traumatic pneumothorax is a pneumothorax caused by chest trauma or during medical diagnosis and treatment operations. Artificial pneumothorax is the artificial injection of gas into the pleural cavity for the diagnosis and treatment of intra-thoracic diseases. According to the relationship between pneumothorax and external air, it can be further divided into.
① closed pneumothorax: the pleural fissure is small and closed with lung atrophy and plasmacytic exudation, no more air leaks into the pleural cavity, the intrathoracic pressure approaches or exceeds atmospheric pressure, and the intrathoracic pressure drops after pumping.
(ii) open pneumothorax: the pleural fissure is continuously open, gas flows freely in and out of the pleural cavity with breathing, intrathoracic pressure fluctuates above and below atmospheric pressure, and there is no change in pressure after pumping.
Tension pneumothorax: the pleural fissure is a one-way valve or piston, the fissure opens when inhaling, air enters the pleural cavity; when exhaling, the fissure closes, gas cannot be discharged, resulting in the accumulation of more and more air in the pleural cavity, the intrathoracic pressure rises rapidly to positive pressure, and then becomes positive shortly after pumping to negative pressure. This kind of pneumothorax causes the greatest pathophysiological changes, and can lead to sudden death if not treated in time to decompress. In addition, there are some special pneumothoraxes, such as menstrual pneumothorax, pregnancy combined pneumothorax and elderly spontaneous pneumothorax.
Etiology and pathogenesis
Under normal circumstances, there is no gas in the pleural cavity because the total partial pressure of various gases in the capillary blood is only 706 mmHg, which is 54 mmHg lower than the atmospheric pressure, and the negative pressure in the chest cavity during the respiratory cycle is caused by the outward expansion of the thorax and the inward elastic retraction of the lung. The presence of gas in the thoracic cavity occurs only in three cases.
(i) a breach is created between the alveoli and the thoracic cavity, and gas will enter the thoracic cavity from the alveoli until the pressure difference disappears or the breach closes.
② trauma to the chest wall producing traffic to the thoracic cavity.
(iii) The presence of gas-producing microorganisms in the thoracic cavity. Clinically, the first two conditions are mainly seen. Spontaneous pneumothorax is one of the most common medical emergencies, with an annual incidence of 18-28/100,000 in healthy adult males and 1,2-6/100,000 in females. the mortality rate of pneumothorax in adult males in the UK between 1991 and 1995 was 1,26/million and 0,62/million in females. Spontaneous pneumothorax is divided into primary and secondary pneumothorax according to the presence or absence of a cause. Primary pneumothorax occurs in healthy individuals without clear underlying lung disease, but rupture of subpleural pneumomediastinum may be the main mechanism of pneumothorax, and smoking is one of the causes of pneumomediastinum in healthy individuals. Secondary pneumothorax occurs in patients with underlying pulmonary disease. The onset of pneumothorax does not appear to be significantly related to somatic activity. Primary pneumothorax usually occurs in higher individuals, with a lower incidence in women. Pleural pressure rises progressively from the base to the apex of the lung, so high individuals have significantly higher alveolar expansion pressure at the apex than at the base of the lung and are theoretically more likely to develop subpleural pneumothorax. The recurrence rate of primary pneumothorax within 4 years is 54%, and single risk factors include smoking, height of male patients, and patients older than 60 years. Risk factors affecting the recurrence of secondary pneumothorax include pulmonary fibrosis and emphysema.
Clinical manifestations
(A) Symptoms: The onset of the disease is mostly acute, with the typical symptoms being sudden onset of chest pain, followed by chest tightness or dyspnea, and an irritating dry cough. There are also patients with slow onset and even no conscious symptoms. Some patients have triggers such as coughing hard, holding heavy objects, breath-holding or strenuous activities before the onset of the disease, while many patients develop the disease during normal activities or quiet rest. The severity of symptoms depends on the urgency of the onset, the degree of lung atrophy, the primary lung disease, and the status of pre-existing cardiopulmonary function. Many patients (especially those with primary pneumothorax) already have pneumothorax a few days before the onset of symptoms, and the longer this phase, the more likely it is that re-expansion pulmonary oedema (RPO) will occur. In general, patients with secondary pneumothorax have more severe symptoms than patients with primary pneumothorax, and the degree of respiratory distress is not proportional to the degree of pneumothorax. The presence of tension pneumothorax should be considered when the patient has hemodynamic disturbances.
(ii) Signs: The signs of pneumothorax depend on the amount of air accumulation. A small amount of pneumothorax may have no obvious signs. When the amount of gas is large, the affected side of the chest is full, the respiratory movement is weakened, the palpation fibrillation is weakened or disappeared, the percussion bulge, and the auscultation breath sounds are weakened or disappeared. In patients with emphysema complicated by pneumothorax, although the respiratory sounds are weakened on both sides, the weakening on the pneumothorax side is more obvious, even if the amount of pneumothorax is not much, so attention should be paid to the left-right comparison and the up-down comparison during percussion and auscultation. The mediastinum is shifted to the healthy side when there is a large amount of pneumothorax. In the case of right-sided massive pneumothorax, the hepatic turbid boundary is shifted downward, and in the case of left-sided pneumothorax or mediastinal emphysema, a click sound or high-pitched metallic sound consistent with the heartbeat is heard at the left sternal border (Ham-man sign). The presence of tension pneumothorax should be considered when the patient presents with cyanosis, profuse sweating, severe shortness of breath, tachycardia and hypotension.
Auxiliary examinations
(A) Imaging examination: X-ray examination is an important method to diagnose pneumothorax. Chest X-ray is a routine means of pneumothorax diagnosis. If there is a high clinical suspicion of pneumothorax and the posterior anterior chest X-ray is normal, a lateral chest X-ray or lateral recumbent chest X-ray should be performed. Most of the pneumothorax chest films have clear pneumothorax line, which is the junction line between the atrophied lung tissue and the gas in the pleural cavity, showing the convex line shadow, and the pneumothorax line is a translucent area without lung texture outside, and the compressed lung tissue inside the line. The mediastinum and heart can be displaced to the healthy side when there is a large amount of pneumothorax. In the case of combined pleural effusion, the pneumothorax surface can be seen. The diagnosis of restricted pneumothorax is easily missed during posterior-anterior X-ray examination, and lateral chest radiographs can assist in the diagnosis. A mediastinal emphysema should be considered if there is a transilluminated band around the parietal border of the heart. CT is more sensitive and accurate than X-ray chest radiograph for the differentiation of small pneumothorax, limited pneumothorax, and pneumomediastinum from pneumothorax. The basic CT manifestation of pneumothorax is the appearance of extremely low-density gas shadow in the pleural cavity, accompanied by different degrees of compression and atrophy changes of lung tissue.
(b) The volume of pneumothorax, as far as volume is concerned, is difficult to be estimated accurately from X-ray chest film. Moreover, there is a tendency to underestimate the volume of pneumothorax on X-rays because it is a two-dimensional image, whereas the pleural cavity is a three-dimensional structure.The 1993 British Thoracic Society guidelines classify pneumothorax into three categories [9]: small volume: small amount of gas at the peripheral edge of the lung; medium volume: the lung is compressed to halfway from the cardiac margin; and large volume: the lung contains no gas and is separated from the diaphragm. The pneumothorax volume estimated by this method is often lower than the actual size. 2003 British Thoracic Society guidelines state that the pneumothorax volume approximates the ratio of the cube of the lung diameter to the cube of the hemithorax diameter at the level of the pulmonary hilar, and if the lung diameter on posterior anterior radiograph is 9 cm and the hemithorax diameter is 10 cm, then a 1 cm pneumothorax accounts for approximately: (103 C 93) ÷ 103 = 27% of the hemithorax volume. Similarly, a 2 cm pneumothorax accounts for 49% of the hemithorax volume. If the approximate distance from the lung margin to the chest wall at the time of pneumothorax is <1 cm, then needle aspiration is not recommended. However, since the actual volume of a pneumothorax with a 2 cm distance from the lung margin to the chest wall represents approximately 50% of the unilateral chest volume, it should be considered a massive pneumothorax and, if circumstances permit, aspiration is safe. Therefore, the British Thoracic Society has recently defined a "small" pneumothorax as a distance of <2 cm from the lateral chest wall to the lung margin at the level of the hilar, and a "large" pneumothorax as a distance of ≥2 cm from the lateral chest wall to the lung margin.
If the volume of pneumothorax needs to be accurately estimated, CT scan is the best method. In addition, CT scan is the only effective means to differentiate pneumothorax from certain difficult cases (e.g., surgical emphysema with asphyxia due to insignificant lung compression, complex cystic lung disease with suspicious pulmonary pneumothorax, etc.).
(iii) Intrathoracic pressure measurement: it helps in pneumothorax typing and treatment.
(D) Blood gas analysis and pulmonary function tests: Most patients with pneumothorax have abnormal arterial blood gas analysis, with PaO2 below 80 mmHg in more than 75% of patients. 16% of patients with secondary pneumothorax have PaO2 < 55 mmHg and PaCO2 > 50 mmHg. pulmonary function tests are not recommended because they are not very helpful in detecting the occurrence of pneumothorax or the size of the volume.
(E) Thoracoscopy: It can clarify the site of the pleural rupture and the underlying lesion, and can also provide treatment.
Disease diagnosis
The diagnosis of pneumothorax is usually not difficult based on clinical manifestations, signs and imaging data. Although clinical manifestations including the degree of dyspnea are not reliable indicators of the size of pneumothorax volume, pneumothorax can often be detected based on symptoms and physical examination. Many patients, especially those with primary pneumothorax, do not present to the hospital for several days after the onset of symptoms because they are mild, and 46% of patients with pneumothorax present to the hospital after 2 days. This clinical feature is important because the recurrent pulmonary edema that occurs after lung re-expansion may be related to the length of time the lung has been compressed.
The diagnosis of the type of pneumothorax (closed, open, tension) can be clarified by measuring the intrathoracic pressure.
Differential diagnosis
1. Pneumomediastinum: Pneumomediastinum has a slow onset and a long course, while pneumothorax often has a rapid onset and a short history. x-ray examination of pneumomediastinum is a round or oval translucent area, located in the lung field, which still has a fine striated texture, while pneumothorax is a striped shadow, located in the field of the lung within the chest cavity. Pulmonary herpes in the peripheral parts of the lung are easily misdiagnosed as pneumothorax, and the line of pulmonary herpes on the chest film is concave toward the lateral chest wall; while the convex side of pneumothorax is often toward the lateral chest wall, and chest CT helps in the differential diagnosis. After a longer period of observation, the size of pulmonary blister rarely changes, while the form of pneumothorax changes gradually and finally disappears.
2. Acute myocardial infarction: there are clinical manifestations similar to pneumothorax, such as acute chest pain, chest tightness, dyspnea, shock and other clinical manifestations, but the patient often has a history of coronary heart disease, hypertension, heart sound nature and rhythm changes, no pneumothorax signs, electrocardiogram or chest X-ray examination helps to differentiate.
3. Pulmonary embolism: underlying disease with embolus source, no pneumothorax sign, chest X-ray helps to identify.
4, chronic obstructive pulmonary disease and bronchial asthma: chronic obstructive pulmonary disease dyspnea is slowly aggravated for a long time, and bronchial asthma has a history of recurrent asthma attacks for many years. When patients with chronic obstructive pulmonary disease and bronchial asthma have sudden worsening of dyspnea and chest pain, the possibility of complicated pneumothorax should be considered, and chest X-ray examination can help to differentiate.
Disease treatment
COPD is the most common disease in patients with secondary pneumothorax, and it is important to watch out for such patients and treat them aggressively because they are tolerant to pneumothorax
Treatment of spontaneous pneumothorax
poorer. Trials have shown that in patients with pneumothorax over the age of 50, as in patients with pre-existing lung disease, treatment with simple suctioning is often ineffective. Therefore, primary pneumothorax over the age of 50 should be treated as equivalent to secondary pneumothorax when considering treatment options. Another factor to consider is the presence or absence of respiratory distress. The rate of natural absorption of gas from the chest cavity is 1,25% to 2,2% of the hemithorax per 24h. Therefore, it takes more than 6 weeks after a pneumothorax if it is allowed to absorb naturally, and this time can be longer if there is a gas leak.
The treatment of pneumothorax is aimed at promoting the reopening of the affected lung, eliminating the cause of the disease and reducing recurrence. The basic treatment measures include conservative treatment, exhaustion therapy, recurrence prevention measures, surgical treatment and prevention of complications.
Conservative treatment
This includes bed rest, oxygen therapy, as well as analgesia, sedation, cough and laxative therapy, as appropriate, to eliminate the causes. Support therapy should be given to those who are weak and have poor nutritional status. Patients who are hospitalized should be given high-flow oxygen. Inhaling high concentrations of oxygen may lower the total pleural capillary gas pressure and increase the pressure difference between the pleural capillary pressure and the intrathoracic pressure, thus promoting the absorption of pleural gas; in addition, it can also raise the blood PO2 and make the partial pressure of nitrogen (PN) fall, thus increasing the PN difference between the pleural cavity and the blood, prompting the nitrogen in the pleural cavity to the blood (nitrogen-oxygen exchange) and promote pulmonary resuscitation. Patients with spontaneous pneumothorax have a gas absorption rate of 1.25% to 2.2% of the hemithorax gas volume per 24 h. It takes 8-12 days for a 15% lung compression to fully reopen, and high-flow oxygenation can increase the absorption rate of pneumothorax by 4 times. However, we should pay attention to the occurrence of oxygen toxicity and avoid continuous inhalation of high oxygen concentration. For the specific method, the oxygen flow rate is 10 L/min, twice a day for 20 minutes each time.
1.Primary pneumothorax with mild symptoms
Patients with closed small spontaneous pneumothorax with mild symptoms only need conservative treatment. Clinical observation is sufficient for more than 80% of patients with pneumothorax volume less than 15%, during which the chance of sustained air leakage is very low. Moreover, the recurrence rate of pneumothorax cases under observation alone is lower than that of those who undergo thoracentesis intervention.
2.Secondary pneumothorax with mild symptoms
Patients with small (< 1 cm) secondary pneumothorax or isolated apical pneumothorax without clinical symptoms may be considered for conservative treatment, but hospitalization for observation is recommended.
3.Symptomatic primary or secondary pneumothorax
These patients are not suitable for conservative treatment and require aggressive treatment, including suctioning or chest tube drainage. Patients with small amounts of pneumothorax (< 2 cm) presenting with significant dyspnea may suggest a tension pneumothorax.
Pneumatic evacuation therapy
1.Simple suctioning
Suction with a small-bore catheter (14-16G) is comparable to the treatment with a large-bore (>20F) chest drain, which has the advantage of reducing pain scores and shortening the number of hospital days.
After simple aspiration for secondary pneumothorax, the patient should be admitted to the hospital for observation for more than 24 h. If there is no improvement, intubation and drainage are required. Simple suctioning has a high failure rate for massive secondary pneumothorax (≥2 cm), especially in patients older than 50 years, and a high recurrence rate, and intubation and drainage should be considered at the outset. Aggressive treatment of the underlying lung disease is also required. Statistical analysis shows a success rate of 30%-80% for simple aspiration therapy. If the total amount of aspirated air is more than 2 or 5 L, the presence of a persistent air leak with lung reopening is considered less likely, and small catheter cannulation for drainage should be chosen at this time.
More than one-third of patients with primary pneumothorax who fail the initial simple aspiration can be revived with a second aspiration. After failure, small catheter cannulation should be considered.
2.Intercostal cannula drainage
A small chest tube (13F) or a larger catheter is used for drainage, depending on the situation. One study showed a low success rate of treating pneumothorax with a small chest catheter (13F) and recommended a larger catheter, however, later findings did not match this and concluded that a smaller caliber chest catheter was more effective and has not been recommended as the preferred treatment, which requires more experience. The average duration of drainage with a small-bore chest tube drainage system compared to a large-bore chest tube drainage system ranged from 2 to 4 days. No problems with catheter obstruction were found in any of these studies. Chemical pleural fixation can still be performed through the small catheter built-in cannula system. If pleural effusion and large air leaks are present and exceed the drainage capacity of the small catheter, then the use of a small catheter is likely to fail, whereas the choice of a larger catheter is more advantageous.
Local intrapleural injection of anesthetic (20-25 ml of 1% lidocaine, i.e., 200-250 mg) significantly reduces pain and does not affect the results of blood gas analysis or the application of chemical pleural fixation.
There is no evidence that clamping improves the success rate or prevents recurrence. The success rate of 24-h pulmonary resuscitation is almost the same with or without preextraction clamping. However, many physicians continue to advocate preextraction clamping for direct observation of small air leaks at the bedside. A chest x-ray should be performed several hours after clamping to detect small or intermittent air leaks and to avoid reintubation.
3. Negative pressure drainage of the chest
There is no evidence to support the routine preference for chest drainage in patients with spontaneous pneumothorax. Negative intercostal pressure drainage should be used for persistent air leaks, incomplete or complete pneumothorax reopening on chest radiographs. Persistent air leakage is often defined as persistent escape of air bubbles from the intercostal catheter 48 h after intubation. In normal subjects, the intrapleural pressure is -8 cmH2O during inspiration and -3 or 4 cmH2O during expiration, and various factors influence the negative pressure in the pleural space during intercostal cannula drainage. Given these differences in physiologic factors, it has been suggested that a negative pressure drainage system of -10 to 20 cmH2O should be used in all patients with slow reopening pneumothorax because it increases negative pressure at an air flow rate of 15 to 20 L/min.
Premature use of negative pressure drainage after thoracic intubation, especially in patients with primary pneumothorax who have been onset for several days, may induce post-relaxation pulmonary edema and should be avoided. Most post-relaxation pulmonary edema does not show up as pulmonary edema on chest radiographs, but the incidence of post-relaxation pulmonary edema is as high as 14%, which is higher than in massive primary pneumothorax and in younger patients (<30 years). Therefore, particular care should be taken when treating young patients with massive pneumothorax, and negative pressure drainage should not be performed immediately in patients with spontaneous pneumothorax.
Internal chemical pleural fixation
Both primary and secondary pneumothorax have a high recurrence rate, which can be reduced by injecting various sclerosing agents into the pleural cavity. Chemical injection into the pleural cavity produces aseptic pleural inflammation causing pleural adhesions. Many sclerosing agents have been studied in the last decade. Tetracycline is currently recommended as the first-line sclerosing agent for the treatment of primary and secondary pneumothorax. Minocycline and doxycycline have been used as sclerosing agents in studies in animal models.
Injection of 500 mg of tetracycline through a chest tube does not actually significantly reduce the recurrence rate of pneumothorax compared to patients with pneumothorax drained by chest tube alone. Switching to 1500 mg of tetracycline resulted in a significant decrease in the recurrence rate of pneumothorax without significant comorbidities. Therefore, this dose can be used as a routine dose for medical pleural fixation. If tetracycline pleural fixation fails, pharmacologic and surgical pleural fixation can still be performed with talcum powder.
Surgical treatment
Surgical treatment needs to be considered in the following cases.
1.Recurrence of ipsilateral pneumothorax
2.The first pneumothorax on the opposite side
3.Spontaneous pneumothorax occurring on both sides at the same time
4. Persistent air leak or failure to reopen the lung after 5~7 days of intercostal drainage
5.Spontaneous hemopneumothorax
6.High risk occupation (such as pilot, driver, etc.)
7.Pregnancy
The patient’s wish is also a factor to be considered. Some patients with primary pneumothorax, even if not due to occupational factors, choose surgery after weighing the risk of recurrence against the pros and cons of chronic pain, physical discomfort and medical expenses.
1.Open-heart surgery
To prevent recurrence of pneumothorax, cautery, ligation or suturing of the concomitant pulmonary blister at the site of the pleural leak to close the leak is necessary. The postoperative pneumothorax recurrence rate of open-chest surgery is very low. The failure rates for ligation/excision of pulmonary blisters, open pleurodesis, and apical or total lung wall pleurodesis are all less than 0,5%. The combined incidence of thoracotomy complications in pneumothorax patients is 3, 7%, mostly sputum retention and postoperative infection. In general, open thoracotomy is performed with unilateral lung ventilation, and a dirty pleurodesis, pneumonectomy, pneumomediastinum ligation or pleurodesis is performed in the lateral thoracotomy.
2.Surgical chemical pleural fixation
Since talcum powder is cheap and has a similar success rate (85-90%) as sclerotherapy for complex pneumothorax as thoracoscopic treatment, talcum powder pleural fixation is currently stirring up renewed interest. The success rate of talcum powder pleural fixation for pneumothorax is 91%. Compared to tetracycline pleural fixation, talcum powder pleural fixation is a less difficult or less painful procedure, and although talc doses range from 2 g to 10 g, there are no controlled trials to demonstrate better outcomes with larger doses. Until the exact dose is determined, treatment with lower doses (2 g to 5 g) is recommended. Talc powder and suspensions have similar success rates and either may be used. The failure rate of talcum powder pleural fixation (9%) is relatively high compared to surgical pleurodesis, and therefore talcum powder pleural fixation should not be the treatment of choice for primary spontaneous pneumothorax requiring surgical treatment. For patients who are unwilling to undergo surgical treatment or are too weak to tolerate conventional anesthesia, pleural fixation with tetracycline or talcum powder injected through an intercostal cannula may be considered.
Side effects of talcum powder pleural fixation include.
(i) adult respiratory distress syndrome, the occurrence of which is related to the size of the talcum powder particles used.
② abscess chest, a complication that rarely occurs with the correct use of sterilized talcum powder.
③ Pneumonia and respiratory failure.
3.Small incision thoracotomy through the anterior axillary line
Becker et al. proposed in the 1970s a small thoracotomy through the anterior axillary line (the incision is about 5-6 cm long), through which apical pleurodesis or exenteration can be performed, and subpleural pulmonary blisters at the apex of the lung can be carefully examined and ligated if necessary. The average length of stay for this procedure is 6 days, the recurrence rate is 0,4%, and the complication rate is 10%, with the vast majority of complications being minor. The above information makes this procedure an ideal choice for the treatment of complex spontaneous pneumothorax.
4.TV-assisted thoracoscopic surgery (VATS)
Compared with surgery, less information is available on VATS for spontaneous pneumothorax. In terms of complications and length of hospital stay, VATS has advantages over open-heart surgery. The complication rate of the least invasive procedure may be similar to that of open-chest surgery, about 8-12%. the recurrence rate of pneumothorax after VATS is 5-10%, which is higher than that of open-chest surgery, which is 1%. Although the success rates for thoracoscopic pneumonectomy, pleurectomy, pleurodesis, and surgical pleural fixation are high, there are concerns that VATS performed under local anesthesia with inhaled nitrous oxide may cause progressive unilateral pulmonary ventilation difficulties and may also make it more difficult to examine the entire surface of the dirty pleura and increase the risk of missing pneumomediastinum.
Some studies suggest that VATS may be more appropriate for young patients with complex or recurrent primary pneumothorax and less appropriate for secondary pneumothorax. For patients with secondary pneumothorax, open-chest surgery with pleural repair remains the currently recommended approach, while VATS should be used as an alternative for patients who cannot tolerate open-chest surgery because of poor lung function.
Complications and their treatment
1, hemopneumothorax: pneumothorax bleeding is caused by the tearing of blood vessels in the pleural adhesion zone, and bleeding can mostly stop by itself after lung reopening. If the bleeding continues, exhaustion, hemostasis, blood transfusion and other treatments are ineffective, open-chest surgery should be performed to stop the bleeding.
2, pneumothorax: caseous pneumonia, necrotizing pneumonia and lung abscess caused by Mycobacterium tuberculosis, Staphylococcus aureus, Mycobacterium pneumoniae, anaerobic bacteria, etc. can be complicated by pneumothorax, which should be urgently drained and exhausted, and effective antibacterial drug treatment (systemic and local) should be selected. Bronchopleural fistulas need to be treated surgically if they persist.
3, mediastinal emphysema and subcutaneous emphysema: after tension pneumothorax aspiration or closed drainage, subcutaneous emphysema of the chest wall may appear along the needle hole or incision. The high-pressure gas enters the interstitial lung and enters the mediastinum via the vascular sheath through the pulmonary hilum, and then along the fascia into the subcutaneous tissue of the neck and subcutaneous thoracic abdomen. The chest x-ray shows a transparent band in the subcutaneous and mediastinal area. The subcutaneous emphysema and mediastinal emphysema can be absorbed by themselves with the decompression of gas in the pleural cavity. If the tension of the mediastinal emphysema is too high and affects breathing and circulation, suprasternal fossa puncture or incision can be performed to vent the air.
Management of complications
1.Pneumothorax combined with pregnancy
Although the incidence of pneumothorax in women is lower than that in men, pneumothorax in women of childbearing age is not uncommon. The recurrence rate of pneumothorax during pregnancy and delivery is high, thus posing a potential hazard to the mother and fetus. Early literature recommended aggressive treatment modalities, such as prolonged chest drainage, thoracotomy, or early termination of pregnancy. In recent years, a change in opinion has been observed, suggesting that conservative treatment modalities can be equally effective. If the mother is not in respiratory distress, the fetus is not in discomfort, and the pneumothorax is <2 cm then it can be temporarily observed. If there is a persistent air leak then chest tube drainage is recommended. A less invasive television-assisted thoracoscopic procedure (VATS) can be chosen after delivery to avoid recurrence in subsequent pregnancies.
To avoid recurrence of pneumothorax during spontaneous delivery and cesarean section, the safest way is to induce the fetus before full term using forceps or suction under epidural anesthesia. If a cesarean section must be chosen, needle anesthesia is more appropriate.
2.Catamenial pneumothorax (CPTX)
It is a special type of spontaneous pneumothorax, clinically characterized by recurrent spontaneous pneumothorax in women during the menstrual cycle, the pathogenesis of which is still unclear and may be related to endometriosis and diaphragmatic foramen ovale. It predominates on the right side, but it also occurs on the left side or bilaterally. Patients often have a combination of endometriosis in the pelvic, thoracic, and abdominal cavities and the presence of a small diaphragmatic foramen ovale. Spontaneous shedding of ectopic endometrium in the diaphragm and/or pleura and lungs, which occurs during the menstrual cycle, causing spontaneous pneumothorax is the main cause of CPTX. In addition, uneven contractions during menstruation induce gas to enter the uterine cavity and enter the abdominal cavity via the fallopian tubes, at which time the ectopic endometrium occluding the diaphragmatic micropores is shed, the diaphragmatic channels open, and gas enters the thoracic cavity and develops.
The treatment of menstrual pneumothorax requires the collaboration of respiratory, thoracic and obstetrician-gynecologists. The treatment is achieved by changing the patient’s menstrual cycle to avoid the occurrence of endometrial shedding. This method is indicated for older patients who do not need to have children. Surgical treatment is the best option for adolescent patients with clear CPTX endometriosis site, poor results of medical treatment, tension pneumothorax, those with significant pleural thickening to pulmonary expansion insufficiency, and those between 10 and 19 years of age. The options are simple diaphragmatic notch repair, partial diaphragmatic or pleurodesis, partial lung resection with folded sutures, or simple sutures. For women who are not of childbearing age, gynecological surgery including tubal ligation, partial oophorectomy, and hysterectomy may also be an option. Surgical resection can reduce the recurrence rate of pneumothorax to less than 2%, and the most accurate efficacy is open thoracotomy plus gynecological surgery (especially hysterectomy), which is almost recurrence-free.
3.AIDS combined with pneumothorax
More than 5% of patients with AIDS are combined with pneumothorax, and 40% of patients are bilateral pneumothorax. The proportion of patients with spontaneous pneumothorax combined with AIDS is nearly 25%. Pneumosporidiosis (Pneumocystis carinii pneumonia) is the most important risk factor for the development of pneumothorax in patients with AIDS, with imaging manifestations such as cysts, pulmonary bullae or pulmonary blisters. Studies have shown that pentoxifylline aerosol prophylaxis is an independent risk factor for the development of pneumothorax. In addition, the application of systemic glucocorticoids is also a risk factor for the development of this group of patients.
Patients with AIDS who develop Pneumocystis carinii infection combined with pneumothorax are often characterized by persistent air leakage, difficulty in treatment, recurrence and high mortality. Moreover, the more immunosuppressed the patient is, and the lower the CD4 count, the worse the outcome of pneumothorax treatment. Treatment methods include closed chest drainage, pleurodesis or partial pleurodesis. It is often difficult to treat pneumothorax with suction alone.